A flexible intermediate bulk container (FIBC) or a bulk bag is a large container of flexible fabric that is used to store and transport heavy loads of flowable products such as seeds, nuts, sand, fertilizer and granules or pellets of plastic. The bags are constructed with woven polypropylene or other equivalent fabrics, and often have a large opening at their top and a spout that can be closed at their bottom. A typical bulk bag can be dimensioned to hold approximately 50 cubic feet of bulk cargo. A typical bulk bag is constructed with four heavy duty strap loops that are positioned at four corners of the bag around the top opening of the bag. A bulk bag filled with bulk cargo can be lifted and transported by a forklift with the forks of the forklift each passing through pairs of adjacent strap loops of the four strap loops. A bulk bag filled with bulk cargo can also be transported by being positioned on a pallet that is lifted by a forklift.
The bulk cargo transported in a bulk bag is unloaded from the bulk bag by a bulk bag unloader. FIG. 1 is a representation of a typical unloader 10. The unloader 10 has a rigid, stationary framework 12 supporting the component parts of the unloader 10. A hopper 14 is supported by the framework 12 at a bottom of the unloader. A rail 16 is supported by the framework 12 at a top of the unloader. The rail 16 extends over the top of the hopper 14 and over an area adjacent the hopper 14.
A trolly 22 having a hoist 24 is provided on the rail 16. The trolly 22 is moveable on the rail 16 from one end of the rail 16 where the hoist 24 is positioned adjacent the hopper 14 to an opposite end of the rail 16 where the hoist 24 is positioned above the hopper 14.
A cable 26 extends downwardly from the hoist 24. The bottom of the cable 26 is connected to an X-shaped lifting member 28. The lifting member 28 has four arms 32 with hooks 34 at the distal ends of the arms.
A conveyor 36 is positioned beneath the hopper 14. The conveyor 36 receives bulk cargo dispensed from the hopper 14 and conveys the bulk cargo away from the unloader 10.
In operation of the bulk bag unloader 10, a bulk bag 38 containing bulk cargo is first positioned adjacent the hopper 14 of the unloader 10. The hoist 24 is then operated to lower the X-shaped lifting member 28. The lifting member 28 is lowered a sufficient distance to enable the four strap loops on the bulk bag 38 to be engaged in the four hooks 34 of the lifting member 28. Engaging the four strap loops 40 of the bulk bag 38 in the four hooks 34 attaches the bulk bag to the lifting member 28 of the bulk bag unloader 10.
The hoist 24 is then operated to retract the cable 26 and lift the bulk bag 38 suspended by its four strap loops 40 from the lifting member 28. The bulk bag 38 is raised a sufficient distance to position the bulk bag above the top of the hopper 14. The trolley 22 is then operated to move the lifted bulk bag 38 from its position adjacent the hopper 14 to a position of the bulk bag 38 over the hopper 14.
With the bulk bag 38 positioned over the hopper 14, the spout at the bottom of the bulk bag can then be opened. Opening the spout allows the bulk cargo contained in the bulk bag 38 to pour from the spout and into the top of the hopper 14. When all of the bulk cargo has exited the bulk bag 38 into the hopper 14, the trolley 22 is then operated to move the emptied bulk bag 38 from its position over the hopper 14 to a position adjacent the hopper 14. The hoist 24 is then operated to lower the emptied bulk bag 38 a sufficient distance to enable the strap loops 40 of the emptied bulk bag 38 to be removed from the four hooks 34 of the lifting member 28. The process of attaching a bulk bag 38 containing bulk cargo to the lifting member 28, and then moving the bulk bag 38 containing bulk cargo to a position over the hopper 14 where the bulk bag 38 can be emptied is repeated.
It can be appreciated that the above described repeated sequences of unloading bulk cargo from bulk bags to a hopper is significantly time consuming.
There are existing continuous bulk cargo unloaders that use vacuum pressure to draw a stream of bulk cargo to a hopper which then dispenses the bulk cargo to a conveyor. However, removing an existing bulk bag unloader from its location and replacing it with a new continuous bulk cargo unloader can be very expensive.